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Document SA_NOCLDWAIT.
Make all the SA_* flags go into a tagged list, to improve readability.
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svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=29341
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@ -29,7 +29,8 @@
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)sigaction.2 8.2 (Berkeley) 4/3/94
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.\" From: @(#)sigaction.2 8.2 (Berkeley) 4/3/94
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.\" $Id$
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.\"
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.Dd April 3, 1994
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.Dt SIGACTION 2
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@ -163,9 +164,10 @@ of the signal are ignored and discarded.
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.Pp
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Options may be specified by setting
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.Em sa_flags .
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If the
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.Dv SA_NOCLDSTOP
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bit is set when installing a catching function
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The meaning of the various bits is as follows:
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.Bl -tag -offset indent -width SA_RESETHANDXX
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.It Dv SA_NOCLDSTOP
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If this bit is set when installing a catching function
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for the
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.Dv SIGCHLD
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signal,
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@ -173,23 +175,34 @@ the
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.Dv SIGCHLD
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signal will be generated only when a child process exits,
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not when a child process stops.
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Further, if the
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.Dv SA_ONSTACK
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bit is set in
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.Em sa_flags ,
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the system will deliver the signal to the process on a
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.It Dv SA_NOCLDWAIT
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If this bit is set when calling
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.Fn sigaction
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for the
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.Dv SIGCHLD
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signal, the system will not create zombie processes when children of
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the calling process exit. If the calling process subsequently issues
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a
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.Xr wait 2
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(or equivalent), it blocks until all of the calling process's child
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processes terminate, and then returns a value of -1 with errno set to
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.Dv ECHILD .
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.It Dv SA_ONSTACK
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If this bit is set, the system will deliver the signal to the process
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on a
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.Em "signal stack" ,
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specified with
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.Xr sigaltstack 2 .
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If the
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.Dv SA_NODEFER
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bit is set, further occurrences of the delivered signal are not
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masked during the execution of the handler.
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If the
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.Dv SA_RESETHAND
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bit is set, the handler is reset back to
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.It Dv SA_NODEFER
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If this bit is set, further occurrences of the delivered signal are
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not masked during the execution of the handler.
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.It Dv SA_RESETHAND
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If this bit is set, the handler is reset back to
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.Dv SIG_DFL
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at the moment the signal is delivered.
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.\" Still missing:
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.\" .It Dv SA_SIGINFO
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.El
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.Pp
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If a signal is caught during the system calls listed below,
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the call may be forced to terminate
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@ -369,7 +382,14 @@ The
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.Dv SA_NODEFER
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and
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.Dv SA_RESETHAND
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are intended for backwards compatability with other operating systems.
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flags are intended for backwards compatability with other operating
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systems. The
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.Dv SA_NOCLDSTOP ,
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and
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.Dv SA_NOCLDWAIT
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.\" and
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.\" SA_SIGINFO
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flags are featuring options commonly found in other operating systems.
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.Sh SEE ALSO
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.Xr kill 1 ,
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.Xr kill 2 ,
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@ -382,6 +402,7 @@ are intended for backwards compatability with other operating systems.
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.Xr sigsetmask 2 ,
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.Xr sigsuspend 2 ,
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.Xr sigvec 2 ,
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.Xr wait 2 ,
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.Xr setjmp 3 ,
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.Xr siginterrupt 3 ,
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.Xr sigsetops 3 ,
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